Furnace grate



April 8, 1930. w. M. DUNCAN 1,753,369

FURNACE GRATE Filed Septv 1'7, 1926 3 Sheets-Sheet 1 Jim April 8, 1930. w. M. DUNCAN 1,753,359

FURNACE GRATE Filed Sept. 1'7, 1926 3 Sheets-Sheet 2 //VVE/V 70R 14 M. Du/v CAN A TTORNEL/S l atented Apr. 8, I930 WILLIAM M. DUNCAN, OF- .ALTON, ILLINOIS FURNACE GRATE Application filed September 17, 1926. Serial No. 136,052.

This invention relates to improvements in furnace grates, and more partlcularly to a mechanically driven grate adapted to feed ashes and other residualmatter from the bottom of a furnace. The preferred form of the invention comprises grate members located adjacent to each other and rotating in opposite directions to draw the residual matter through the grate structure. One of the objects of the invention is to forcibly remove the ashes from the bottom of a furnace, so that the ashes will. not interfere with the admission of air to the bottom of the fuel bed. The grate members can be rotated at any desired speed to remove the ashes at the desired rate, and the air can be forced under pressure through the grate to provide for a high rate of combustion in the furnace.

kind having its elements so arranged that the air can freely enter through the grate while the ashes are being withdrawn. A further object is to distribute the air at the grate so as to provide for substantially uniform combustion in the fuel adjacent to the grate.

With the foregoing and other objects in view, the invention comprises the novel construction, combination and arrangement of parts hereinafter more specifically described and illustrated in the accompanying drawings, wherein is shown the preferred embodiment of the invention. However, it is to be understood that the invention comprehends changes, variations and modifications which a come within the scope of the claims hereunto appended.

Fig. I is a horizontal section through the combustion chamber of a furnace, showing a grate constructed in accordance with my invention.

Fig. II is a vertical section approximately through the center of the furnace, showing a portion of the grate in elevation.

Fig. III is a vertical section on the line IIIIII in Fig. II.

Fig. IV is a side view, partly in section, illustrating the gearing whereby the grate members are rotated.

Another object is to produce a grate of this.

portion is spaced from an adjacent grate Fig. V is a detail viewshowing one of the grate wheels. 1 I

F ig; VI is a fragmentary plan view illustrating a modification.

Fig. VII is a longitudinal section of one of the grate members shown in Figz'V.

The furnace shown by F igs'. I to IV comprises a combustion chamber 1 above an ash pit 2, the latter having an inlet 3 for air under pressure and a sealing plate 4: extending into a bodyof water 5 to prevent leakage of air from the ash pit. I

The grate structure shown in Figs. I to V comprises a series of horizontal shafts 6 arranged parallel with each other and rotatably mounted in bearings 7. Each shaft 6 has anon-circular portion between its ends, and arow of circular grate wheels'8 is mounted on the non-circular portion of each shaft.

Each of said wheels has .a toothed periphery, 7 j

a central aperture conforming to the noncircularv portion of the shaft, and a boss 9 on one. side (Fig; V). whereby the peripheral,

wheel. 5* Gear wheelslO are secured to the respective shafts 6, the gear wheel on each shaft being in mesh with the-gear wheel Jon'an adjacent shaft, so as to rotate the adjacent shafts in opposite directions. The driving means in- L9 eludes a pulley l1 fixedto one ofthe shafts 6,

and thisv pulley is rotated continuously by any suitable power mechanism.

The peripheral projections, or teeth, on I each rowrof g'rate'wheels 8 are adjacent to but separated slightly from the corresponding projections on an adjacent row, and when these wheels are rotated in opposite'd'irections, as indicated by arrowsin Fig. III, the downwardly moving side of one row of '9 wheels will cooperate with the downwardly moving side of an adjacent row to forcibly draw residual matter through the grate.

F uel-supporting baffles 12 are located immediately above the adjacent rising sides of 35 the rows of grate wheels. The baffles shown in Figs. I and III are stationary bars extending across the bottom of the combustion chamber and provided with apertures '13 for I A the delivery of air to the fuel abovesaidlbars.

can freely rise between the wheels.

Since the grate wheels 8 are separated from each other, as shown in Figs. I and II, air The baffies 12 aid in the distribution of the air by preventing the delivery of an undue volume of air between the rising sides of the rotary gratewheels, and they also separate the ashes and fuel from these rising. sides.

Figs. VI and VII illustrate conical grate members 8 fixed to shafts 6 provided with gear wheels 10 whereby adjacent grate mei bers 8 are rotated in opposite directions. A driving pulley 11 is fixed to one of the shafts 6. The grate members .8 are hollow, as shown in Fig. VII, and they have peripheral projections 14v .which force the residual matter through the grate structure. Apertures 115 are formed in the grate members 8 to. provide for the admission of. air through these members.

The grate members 8v are arranged around acent-ral .core 16, and each of said grate mem bers has a trunnion17 extending from. its inner, end and mounted in .the central core, as shown inFig. VII. Baffle bars 12 are located above the rising sides of adjacent grate members 8.

I'claim;

1. In a furnace grate, rotatable fuel-supporting members located adjacent to each other to forina grate, a driver whereby said adjacent members are rotated in opposite directions to force residual matter through the grate, and fuel-supporting baffles each located immediately above rising portions of two of the rotating fuel-supportmg .members.

2. Inia furnace grate, rotatable fuel-supporting -memberslocated adjacent to each other to forma grate, a driver whereby said adjacent members are rotated in opposite d-irections to force residual matter through .the grate, and fuel supporting baflles each located immediately above rising portions of two of ,the rotating fuel-supporting :members, said baflles beingremote from the downwardly .Inoving pontions ofthe rotating fuel-supporting members, .so as to permit free discharge of the residual matter.

3. In a furnace grate, rotatable fuel-supporting members located adjacent to each other to form a grate, a driver whereby said adjacent members are rotated in opposite direction to force residualmatter through-the gr'ate,and fuel-supporting baffles eachlocated immediately above rising portions of two of the rotating fuel-supporting members, said baflles being provided with apertures .for the delivery of air .therethrough. i

4. In a furnace grate, circular fuel-supporting members located adjacent to each other, driving means whereby-said adjacent circular members are rotated in. opposite directions so that the downwardly moving side ofleach of said membrs will cooperate with .thedownwardly moving. side of an adjacent ;WILLIAM nnUNoAN. 

